Under the direction of new Chief of Staff BB Yates, Daniel Miller, Robert Kirsch, Valerie Edwards and the rest of Berlin Station embark on an unsanctioned operation to uncover a possible Far Right terrorist attack.

In a 24-hour episode set completely in Spain, Daniel uses Hector to further his mission with Otto, much to Hector's dismay.

Valerie works to obtain intel on the Far Right while Robert's teenage son Noah arrives in Berlin and asks questions. Meanwhile, Frost agrees to the Ambassador's request to spy on Berlin Station.

BB Yates's past is revealed while she juggles keeping Berlin Station's Far Right operation covert or revealing it to Ambassador Hanes; Daniel discovers a lack of trust between Otto Ganz and his daughter.

Robert and Frost travel to Norway to investigate the illegal money trail leading to PfD; BB and Valerie devise a new plan involving a member of the Far Right; Daniel deals with the psychological consequences of his mission.

April weighs telling Robert about Hector's assassination plot; Daniel tries to arrange safe passage out of Berlin for Hector with help from Esther.

Hector is wanted by German authorities for the assassination of Katerina Gerhardt, but Berlin Station begins to discover there is more at play than a jaded ex-CIA officer.

Berlin Station continues to search for the truth behind Katerina Gerhardt's assassination and Nick Fischer's role in it, as a protest outside the US Embassy and calls to turn Hector over escalate.

Valerie Edwards sends Daniel Miller and Robert Kirsch on an urgent mission, where they meet renegade CIA Officer Rafael Torres, and uncover signs of a covert invasion.

Berlin Station follows up on the evidence Kirsch brought home from his mission, crystallizing their theory about a possible upcoming invasion.

The Station enlists Rafael Torres to track down a missing comrade's, Daniel Miller's last known location, leading him to hostile territory. Kirsch visits an old friend.

The explosion of a fishing boat is detected. CIA agent Rafael Torres violates the order of the Station Chief of Berlin Station, and retrieves the burned body that he believes is of missing CIA agent Daniel Miller.

Kirsch and Torres must risk their lives to secure their fallen comrade's location. When B.B. Yates returns to Berlin, the Station must decide whether or not they can trust an emissary of the Oval Office.

Valerie and B.B. rally the support of the 14-Eyes, a powerful intelligence collective. Kirsch and April, using Sofia as bait, trap Sergei. Kirsch offers to swap Sergei for Daniel. April comes clean to her asset, securing the tech for U.S. interests. Esther activates Bruno, a German Special Operator, to locate Daniel. Frost introduces Torres to Hector, whose new identity as a roofer to oligarchs provides a way to infiltrate the Russian elite. Frost investigates one of the soldiers formerly under Krik's command to gain kompromat from his war days.

Valerie is stunned when B.B. betrays her and votes against the 14-Eyes invoking Article 5. April faces the loss of the tech when her assets are arrested and face deportation. Kirsch's spy swap goes horribly awry when Bruno, Esther's officer, is exchanged instead of Daniel. Platov invites Hector and Torres to Krik's dacha, forcing them to navigate the treacherous world of Russian oligarchs. Their mission is upended when Hector falls out of favor with Krik and finds himself human prey in their evening hunt, along with one other prisoner: Daniel.

Daniel and Hector are being hunted by Vassily Krik. They manage to find shelter in a green house in the woods where a well-kept secret will be revealed.

Frost volunteers with Valerie's reluctant consent to rescue Daniel from Krik's estate. When Daniel confronts Frost about his past alias as "Diver" shots are fired. Hector is a secret witness. Krik is arrested by his government. Daniel's body is dumped on the streets of Berlin. Torres uses his cover as a ruse to get Platov to Germany. The Estonian communications network is hijacked, but Sofia can only use her master password by returning to her country.

Mere hours remain before enemy forces topple the Estonian government. Without Langley's backing, Berlin Station acts alone in one final desperate push to prevent the fall of a nation.